Camcorders (video camera recorders) receive video information and convert it to electronic video signal, which is recorded on the storage medium in analog or digital formats. While most conventional camcorders record and display two-dimensional video images, some camcorders are capable of recording particular information required for stereoscopic viewing. When human eyes see a scene, right and left side eyes have two different perspectives due to their separation. The brain fuses these two images and assesses the visual depth. Three-dimensional camcorders need to provide two perspective images for each video frame. In order to provide different viewing angles simultaneously, they usually use two cameras which are separated at a certain distance as human eyes are. FIG. 1 depicts the schematic illustration of a prior art using a pinhole or thin lens model. Cameras 11 and 12 have identical focal length and their image planes are coplanar in space. The distance between optical centers 13 and 14 is 2d. Two cameras have different perspectives for an object 15 and provide a pair of stereoscopic images, which allows three-dimensional viewing. However, these devices tend to be large and heavy, and come at huge cost due to multiple camera systems and their optical axis separation requirement.
Conventional three-dimensional display devices use two perspective images of a scene and provide methods to let each eye see an only intended perspective. While conventional three-dimensional display devices require special glasses for a viewer to see a three-dimensional image from two perspective images, autostereoscopic display devices do not require special glasses. Autostereoscopic devices display two different perspective images concurrently and use barriers to let each eye see the intended image as disclosed by U.S. Pat. No. 6,046,849 to Moseley. Usually, these devices have several viewing areas and the scene appears to leap out of the screen, which provides a virtual-reality environment. These autostereoscopic display devices can be built in the three-dimensional camcorders as electronic viewfinders like normal LCD screens in two-dimensional camcorders in order to find and focus views in the three-dimensional space and replay recorded three-dimensional images or movies.